1. Field of the Invention
The invention relates generally to a method of manufacturing an insulating film in a semiconductor device. More particularly, the present invention relates to a method of manufacturing an insulating film in a semiconductor device, capable of improving the adhesive force and reducing the dielectric constant, in a spin-on dielectric (SOD) film and a hard mask film.
2. Description of the Prior Art
Generally, as a semiconductor device is highly integrated, the size of a conductive layer and the distance between the conductive layer patterns are reduced. As the distance between the conductive layer patterns becomes smaller, and as the capacitance between the patterns is increased, when a device is driven, the transfer of the signal is delayed, consumption of power is increased and a cross talk between lines is generated, thereby degrading the electrical characteristics of the device.
Therefore, in order to prevent degradation of the electrical characteristics of the device, use of an insulating film having a low dielectric constant is required. The insulating film involves a silicon oxide film into which carbon (C) or fluorine (F)-based ions are doped, and organic-based SOD films.
A polymer film among the SOD films is made of similar components to a photosensitive film used as an etch mask in a subsequent patterning process. In order to obtain an etching selective ratio, a hard mask film as a protective insulating film is usually formed on the SOD film. Therefore, it is required that the hard mask film have a good etching selective ratio to polymer, be possibly processed by a low-temperature process, and have a good adhesive force between polymers and a relatively low dielectric constant.
Accordingly, the hard mask film is formed using a silicon oxide film satisfying the above requirement. The silicon oxide film is usually deposited in a plasma method, wherein reaction gases such as SiH4, N2O, N2 etc. are used which can be experienced by a low-temperature process upon deposition, so that its transformation can be prevented. The silicon oxide film used as the insulating film varies its deposition condition, that is, its dielectric constant is changed depending on the supply ratio of the reaction gases (SiH4 and N2O). Thus, in order to form an insulating film having a relatively low dielectric constant, the supply amount of N2O gas must be increased and the supply amount of SiH4 gas must be reduced.
In this case, though the dielectric constant is reduced, a separation between the SOD film and the hard mask film occurs during a subsequent cleaning process since the adhesive force in the interface between the SOD film and the hard mask film becomes poor. It was found that the separation at the interface between the SOD film and the hard mask film is caused by oxidization of the interface of the SOD film by an oxygen atmosphere during deposition process of the hard mask film.
A method of manufacturing an insulating film in a semiconductor device is disclosed which is capable of solving the aforenoted problems. Specifically, a silicon oxide film is deposited to form a hard mask film, wherein the supply amount of gas and the supply amount of a RF power are controlled, respectively, to prohibit oxidization of polymer at an early stage of the deposition process, and to reduce a dielectric constant at a later stage of the deposition process.
A disclosed method of manufacturing an insulating film in a semiconductor device comprises the steps of forming a SOD film on the entire structure to fill the distance between conductive layer patterns and after performing a curing process, forming a hard mask film on the SOD film, wherein the silicon oxide film is deposited by plasma deposition method using SiH4 and N2O as a reaction gas at a low-temperature and at a low-pressure and wherein in a stabilization step, the supply amount of SiH4 is greater than that of N2O and in a deposition step, the supply amount of N2O is greater than that of SiH4.
Also, a method of manufacturing an insulating film in a semiconductor device is disclosed which comprises the steps of forming a first SOD film on a semiconductor device for which a given process is performed and then performing a curing process; forming a hard mask film on the first SOD film and then performing a surface process in-situ; and forming a second SOD film on the first SOD film and then performing a curing process, and then forming a second hard mask film on the second SOD film.
The first and second hard mask films are made of a silicon oxide film, wherein the silicon oxide film is deposited by plasma deposition method using SiH4 and N2O as a reaction gas at a low-temperature and at a low-pressure and wherein in a stabilization step, the supply amount of SiH4 is greater than that of N2O and in a deposition step, the supply amount of N2O is greater than that of SiH4.